I'm going to go look at a 280e tomorrow and wanted to ask besides the battery tray, door bottoms, seam under front bumper where else should I look for rust. The owner said that he does not have time to go have the car checked out and that he was not going the car to leave his sight. Would you buy it without a PPI?

Also, what is a good oil pressure after the car is warm with that motor at what rpm? I really want the car but a little scared to pull the trigger.

In gear at hot idle my 280 runs at 750 RPM and the oil presure is 1.5 bars. After a good long run on the highway it will drop to 1 bar. So at idle if the pressure is inbetween 1 and 2 bars(15-35 PSI) your okay.

Yeah, it's the heat in the engine and oil; the engine parts expand and the tolerances get a bit wider, and the oil thins out a bit.
My '91 103 engine will routinely drop below 1bar (15 PSI) at 600 RPM in Drive on a hot day. it's done this since it was new. The experts say that at idle, any pressure over 4 PSI is OK; and the general rule is 10 PSI for each 1000 RPM.

Simply put: At higher RPM the oil pump is turning faster so the oil pump, which is a gear pump, is turning faster and pumping more oil.

The greater the volume of oil going into the dischage of the pump the greater the PSI at the opening of the discharge. The only way more volume can move through a set sized hole is with an increase in PSI.

When you back off the RPM of the engine drops quicly and so does the RPM of the oil pump. The higher pressure on the discharge side of the pump drops, too. The pressure that is just past the oil pump discharge is where the PSI is measured, so you are seeing the PSI in the discharge area drop as it responds to less oil being pumped.

The PSI then comes back up to normal as the oil volume in the discharge area of the pump is filled up again.

Well, maybe that is not so simple. Bottom line: this is normal and don't worry about it.

Make sure the engine is COLD when you start it. The warm-up valves on these are VERY pricy and tend to go out after about ten years. If the car starts and idles fine when the engine is cold the warm-up valve is OK.

If the seller says he just had to drive the car for a moment then come back when the engine is cold. If you don't you will wish you had.

The valves on these engines are manually adjusted. If you hear a ticking noise coming from the camshaft area it is not a sticking lifter, it is a flat or dished out camshaft. There are two cams on this engine and both are a little over $600 each. You also have to pull the head to replace them.

Not only do the cams go flat, but the cam followers get dished out. These are not cheap either.

Adjusting the valves is easy but you need a special tool to do it quickily. You can do it with a 17mm crowfoot but Hazet makes the special tool and it is about $70. These do show up on Ebay from time to time.

Also check under the car and see if the cat converter is OK. These are pricy as well and tend to go bad about every 200,000 miles.

If you do buy it you can plan on getting about 17 mpg.

On the plus side these are very nice autos to drive around in. Trips of 600 miles a day are not hard to do.